[Nottingham] Open Source equivilent to Thumbsplus?

[John]

I'm looking for an Open Source equivalent to Thumbsplus, the image 
catalog and database program, that allows assigning of keywords to 
records as well as using metadata, file names, folder names to auto 
generate keywords. I've done some googling, but  can only find links to  
'server side' apps, such as copermine, gallery, etc, that don't really 
fit the bill. Here's the tricky bit ~ I need it to be available for 
Windoze as well as Linux (KUbuntu in my case), and I need to database to 
be compatible with both versions, so that it can be shared via a network 
resource. My last resort would be to get my head around WINE, and try 
and get Thumbsplus working in that, but then I would hit licensing 
issues if I wanted to stay legit.

Any Ideas? I'm fairly new to Linux, so 'dumbed down' answers would be 
most welcome :-)